Selective Fluorescent Sensing for Iron in Aqueous Solution by A Novel Functionalized Pillar[5]arene

Abstract Iron ion is one of the most physiologically important elements in metabolic processes, indispensable for all living systems. Since its excess can lead to severe diseases, new approaches for its monitoring in water samples are urgently needed to meet requirements. Here, we firstly report a novel and universal route for the synthesis of a series of pillar[n]arene derivates containing one benzoquinone unit by photocatalysis. With this in hand, an anthracene – appended water – soluble pillar[5]arene (H) with excellent fluorescence sensing potency was prepared. H enabled the ultrasensitive detection of iron ions in aqueous solution with limits of detection of 10−8 M. Over a wide range of metal ions, H exhibited specific selectivity toward Fe3+. More importantly, H could still properly operate in a simulated sewage sample, coexisting with multiple interference ions.


Supporting results and experimental raw data
3.1 1 H NMR 13 C NMR and MALDI-TOF-MS spectra of Qui-OEPns 3.2 1 H NMR and MALDI-TOF-MS spectra of compound 2 3.3 1 H NMR 13 C NMR and MALDI-TOF-MS spectra of compound 3 3.4 1 H NMR 13 C NMR and MALDI-TOF-MS spectra of H 3.5 UV-visible spectroscopy of H upon addition of Fe 3+

General procedure for fluorescence experiments
The solution of H (20 μM) was prepared with pure water.The chloride salts of various ions were dissolved in the solution H.During the fluorescence experiments the concentration of H was kept at 20 μM and the concentration of metal salts was increased gradually according to previously reported method. [2]igure S2. 13 Figure S2.13  C NMR spectrum (150 MHz, CDCl3, 298K) of Qui-DEP5.

Figure S34 .
Figure S34.Calibration curve obtained via determining OD absorption and used for calculating the amount of Fe 3+ concentration.

Synthetic Protocols of water-soluble functionalized pillar[n]arene
3.6 1 H NMR spectra H in the presence of increasing concentration of Fe 3+

Table S1 .
Chemical shift of critical peaks of H in the absence and presence of Fe 3+